This application is the National Stage of International Application No. PCT/JP99/03057, filed on Jun. 8, 1999.
1. Technical field
The present invention relates to a pharmaceutical composition for treating or preventing sleep disorders which comprises (S)-N-[2-(1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl)ethyl]propionamide in combination with at least one active component selected from zolpidem, zopiclone, triazolam and brotizolam.
2. Background art
Sleep disorders can be classified into about 90 different types based on features of the symptoms, cause of the disease, etc. (International Classification of Sleep Disorders (ICSD): In Diagnostic and Coding Manual; American Sleep Disorder Association: Allen Press Inc.: Lawrence, Kans., 1990). Most of the medicines for treating these disorders at present are benzodiazepines and their derivatives. Non-benzodiazepines such as zolpidem, zopiclone, etc., which are comparatively new hypnotics, are structurally different from benzodiazepines, but exhibit the same activities as benzodiazepines through benzodiazepine receptors. It is believed that benzodiazepines lower the activity of information processing by sedating the limbic system and hypothalamus and inducing sleep. Further, it is known that benzodiazepines do not increase REM (rapid eye movement) sleep and increase non-REM sleep only.
On the other hand, it is disclosed in WO 97/32871 that various tricyclic compounds including (S)-N-[2-(1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl)ethyl]propionamide, have an excellent activity as melatonin agonists and are useful for treating or preventing sleep disorders, etc.